I've raised, shown, trained dogs since I was 12. No I don't trade them something when I take a toy away. If I take a toy away they know that is fine, it is MY toy. Of course maybe it is the breed. I've only worked with Cocker Spaniels. Our first two were mean and bit, so I decided I would breed my own and they would be like the breed standard specifies, "above all he should be merry." I've never had one of mine growl over food, or toys or when I trimmed them , clipped nails etc.
They would get their first head trim at 10 days old, so I could check their quality at that point for show.. That followed with nail trims(just a bit off), cleaning ears, doing picky glands etc. If you start with it right off, they will accept it. I realize everyone doesn't whelp their own puppies. But you do need to do these things from the time the puppy comes home. From this would come everything else, like not chewing , not digging, no barking when I said No! In fact NO was all that was needed for practically everything. They didn't get beaten, they didn't wear pinch or spike collars. Didn't use shock collars or cattle prods or anything else.
They just wanted to please - some were much more active than others but they learned appropriate behaviors in time. No I didn't have chickens. But we had a stray cat that adopted us - my dogs had never been near cats. The cat slept in a cardboard box by the outside garage. I had my best stud on leash when he suddenly plunged his head into the box and noticed the cat. He grabbed the cat by the tail - cat totally ignored him. When the cat didn't run, my dog let go. He never tried it again. He also didn't leave anything but a wet spot on the cats fur. My others were soft mouthed also, never left a teeth mark in anything - just slobber.
I have to say a 150 lb. dog that growled at me, wouldn't do that again he would be rehomed. Size makes a mighty difference, and 2 yrs. old is too old to start growling over toys unless he did that when he was younger and got away with it. Sounds like he's got a burr under his saddle and is acting out. Did something new come into his life to make him jealous? Is he getting less attention than usual? Have you overlooked any change in his health. I personally don't think you could ever trust him again unattended. Myself, I wouldn't enjoy dog ownership if I had to watch every second to see if he would behave himself, or slaughter anything he could grab.